Neutron diffraction study of phase transitions in perovskite-type strontium molybdate SrMoO3

The structure of a polycrystalline sample of SrMoO3 has been investigated using powder neutron diffraction from 5 to 300 K, to reveal two structural phase transitions, the first from the cubic Pm3¯m structure with a=3.97629(3) Å to a tetragonal structure in I4/mcm near 266 K and the second to an orthorhombic Imma phase below 125 K. The average Mo–O distance is essentially independent of temperature. The temperature dependence of the octahedral tilting appears typical of a tricritical phase transition.

Variable temperature neutron diffraction measurements of SrMoO3 from 5 K to room temperature show the presence of two phase transitions associated with tilting of the octahedra. On cooling, the structure transforms from cubic (Pm3¯m) to tetragonal (I4/mcm)(I4/mcm) and ultimately orthorhombic (Imma).Figure optionsDownload as PowerPoint slide